Pastor Maldonado has been handed a 10-place grid penalty for Sunday's Monaco
Grand Prix following a moment of madness in final practice.

The winner of the Spanish Grand Prix 13 days ago was hauled before the stewards after the hour-long session for appearing to turn in on Sergio Perez in his Sauber at Portier, the corner before the entry to the tunnel.

Perez immediately reported the incident to his team over the in-car radio, claiming "Maldonado is crazy".

The stewards agreed, which means the Venezuelan has virtually no chance of back-to-back wins after his debut triumph in Barcelona and the first victory for Williams for seven and a half years.

Following the incident with Perez, Maldonado's session then went from bad to worse as he went on to hit a barrier on entry into Casino Square.

The impact sent him colliding into a barrier on the opposite side of the circuit, resulting in him losing his left-rear wheel and severely damaging the bodywork.

Maldonado eventually trundled down the short straight to Mirabeau where he parked up, forcing practice to be red flagged and leaving the team with a race against time to prepare the car for qualifying.

Come the conclusion, Mercedes' Nico Rosberg led the way with a lap of one minute and 15.159 seconds, with the top four drivers covered by just five hundredths of a second such was its close nature.

For the first time this year Ferrari's Felipe Massa appears to be on the pace as he finished just 0.038secs down, followed closely by reigning champion Sebastian Vettel in his Red Bull and the second Ferrari of team-mate Fernando Alonso.

Lotus' Romain Grosjean was 0.286secs adrift in fifth, with the McLarens of Jenson Button and Lewis Hamilton sixth and seventh, the latter just over half a second off the pace.

Michael Schumacher in his Mercedes, Perez and Red Bull's Mark Webber completed the top 10.

Force India's Paul di Resta was also in the wars late on, the Scot riding a bump down the hill out of the tunnel and heading towards the port chicane, forcing him nose first into a barrier.

Di Resta's damage was minimal compared to that of Maldonado, but it was still enough to bring his session to a halt six minutes early.

The HRT of Pedro de la Rosa brought up the rear of the field with a time nearly four seconds down on Rosberg.